Protein Concentrator Vivaspin 500 MWCO: 5,000 dalton Filter materials: PESU Active Membrane Area: 0.5 cm2 Hold up Volume: < 5 ul Dead Stop Volume: 5 ml Rotor Cavity: to fit 2.2 ml conical bottom tube Min.Effective Speed: 3,000g Recommended Speed: 12,000g Max.Speed: 15,000g Pack size: 100 (Non-sterile)